[Codevs] 1014 棋盘染色

  1 #include<cstdio>
  2 #include<iostream>
  3 #include<cstring>
  4 #include<queue>
  5 #define LL long long 
  6 using namespace std;
  7 
  8 const int dir[4][2] = {{0,1},{1,0},{-1,0},{0,-1}};
  9 
 10 bool swi = true;
 11 
 12 struct MAP{
 13     int map[7][7],step,remain;
 14     
 15     MAP(){
 16         memset(map,0,sizeof(map));
 17         step = remain = 0;
 18     }
 19 };
 20 
 21 queue<MAP> q;
 22 
 23 bool HASH[21473650];
 24 
 25 LL GETHASH(MAP now){
 26     LL code = 0;
 27     for(int i = 1;i <= 5;i++){
 28         for(int j = 1;j <= 5;j++){
 29             code = (code<<1)+now.map[i][j];
 30         }
 31     }
 32     
 33     return code%21473648;
 34 }
 35 
 36 bool poicheck(int x,int y){
 37     if(x > 5 || x < 1 || y > 5 || y < 1) return false;
 38     else return true;
 39 }
 40 
 41 int tot = 0;
 42 bool chess[6][6];
 43 void dfs(int x,int y,MAP now){
 44     if(chess[x][y] || !now.map[x][y] || !poicheck(x,y)) return;
 45     chess[x][y] = true;
 46     tot++;
 47     for(int i = 0;i < 4;i++){
 48         int nowx = x+dir[i][0];
 49         int nowy = y+dir[i][1];
 50         dfs(nowx,nowy,now);
 51     }
 52 }
 53 
 54 bool check(MAP now){
 55     int x,y;
 56     for(int i = 1;i <= 5;i++){
 57         for(int j = 1;j <= 5;j++){
 58             if(now.map[i][j]){
 59                 x = i,y = j;
 60                 break;
 61             }
 62         }
 63     }
 64     
 65     memset(chess,false,sizeof(chess));
 66     tot = 0;
 67     dfs(x,y,now);
 68     
 69     if(tot == 25-now.remain) return true;
 70     else return false;
 71 }
 72 
 73 void Input(){
 74     MAP tmp;
 75     
 76     for(int i = 1;i <= 5;i++){
 77         for(int j = 1;j <= 5;j++){
 78             scanf("%1d",&tmp.map[i][j]);
 79             if(!tmp.map[i][j]) tmp.remain++;
 80         } 
 81     }
 82     
 83     tmp.step = 0;
 84     
 85     
 86     
 87     q.push(tmp);
 88 }
 89 
 90 void PUSH(MAP now){
 91     now.step++;now.remain--;
 92     for(int i = 1;i <= 5;i++){
 93         for(int j = 1;j <= 5;j++){
 94             if(!now.map[i][j]){
 95                 now.map[i][j] = 1;
 96                 
 97                 LL code = GETHASH(now);
 98                 
 99                 if(HASH[code]){
100                     now.map[i][j] = 0;
101                     continue;
102                 }else HASH[code] = 1;
103                 
104                 if(check(now)){
105                     printf("%d",now.step);
106                     swi = false;
107                     return;
108                 }
109                 q.push(now);
110                 now.map[i][j] = 0;
111             }
112         }
113     }
114 }
115 
116 void bfs(){
117     while(!q.empty() && swi){
118         MAP tmp = q.front();
119         q.pop();
120 //        cout << ‘A‘;
121         if(check(tmp)){
122             printf("%d",tmp.step);
123             swi = false;
124             return;
125         }
126         
127         PUSH(tmp);
128     }
129 }
130 
131 int main(){
132     
133     Input();
134     bfs();
135     
136     return 0;
137 }